Optical sensor devices comprise sensor elements like photodiodes. Filters are placed above the sensor elements for the purpose of selecting spectral ranges. Optical interference filters are formed by successive layers of different optical materials of distinct refractive indexes. The spectral response, which is represented by the wavelength filter curve, can be adjusted by controlling the thickness of the filter layers. Such interference filters are rather sensitive to the angle of incidence.
The transition wavelength of the filter tends to shift to progressively shorter wavelengths with increasing angle of incidence. Hence the color measurement depends on the angle of incidence. This effect may also adversely affect the computation of derived quantities like color temperature.
WO 2016/005097 A1 discloses an optoelectronic package with lens assembly comprising a lens having an upper surface, a lateral surface surrounding the lens, and a bottom surface. An optoelectronic component is arranged at or near the bottom surface, and an aperture is arranged at the upper surface, so that the lens is arranged between the optoelectronic component and the aperture. Widths of the lens that are defined in a specified lateral direction decrease from a maximal width at or near the bottom surface to a non-vanishing minimal width at the upper surface. The entire lens may be tapered.